Vitte

1. First Program

Level: beginner · Reading time: 3 min · Prerequisite: book/poche/00-how-to-read.html · Last review: 2026-05-09

TL;DR (5 lines)

  • Read the core idea first.
  • Understand one concept at a time.
  • Run small examples.
  • Fix errors early.
  • Move to next chapter only when clear.

Frequent mistakes

  • Skipping prerequisites.
  • Reading without trying examples.
  • Fixing too many errors at once.

Prerequisites: book/poche/00-how-to-read.html. See also: book/chapters/01-starting.html.

Goal

Run a program that returns a value.

Example

entry main at app/demo {
  return 0
}

Why it matters

This pattern is the basis for all the following exercises.

Quick check

What happens if you replace 0 with 1?

Try this

  1. Copy the snippet.
  2. Compile.
  3. Check the return.

If you're stuck

The code above is sufficient: it is valid, readable and executable.

Mini quiz

  1. What is the main goal of this chapter?
  2. Which concept is most important?
  3. What will you try right now?

See also

Next best action

Apply one idea from this chapter in a tiny example, then continue.